Wound dressings form an important segment of the global wound care market. These products are widely used in the treatment of injuries such as wounds, hemorrhages, damaged tissues, and bleeding tissues. The ideal dressing should prevent excessive bleeding and promote rapid healing at a reasonable cost with minimal inconvenience to the patient.
The haemostatic properties of a wound dressing are determined by the texture and the porosity of the material. As regards porosity, the pores of the dressing are usually so tiny that they are not visible to the human eye upon casual inspection. They are, however, of sufficient size not only to permit ample transpiration of skin moisture and wound vapors, but also to permit absorption of blood so that the dressing becomes firmly anchored to the tissue once the blood has coagulated.
Wound dressings should be able to maintain a moist environment around the wound, effective oxygen circulation to aid regeneration of cells and tissue, and a low bacterial load. Wound dressings that are employed during surgery and that remain in the body should be biodegradable and completely resorbable.
Conventional tissue-adhesive wound dressings include fibrin sealants, cyanoacrylate based sealants, and other synthetic sealants and polymerizable monomers. These tissue-adhesives are only suitable for specific applications because of several drawbacks, including release of toxic degradation products, high cost, need for refrigerated storage, slow curing, limited mechanical strength and risk of infection. Therefore, hydrogel tissue adhesives have been developed on the basis of reactive polyethylene glycol (PEG) precursors. However, these hydrogel tissue adhesives swell or dissolve away too quickly, or lack sufficient cohesion, thereby decreasing their effectiveness as surgical adhesive. Moreover, the properties of such PEG-based material cannot be easily controlled.
Haemostatic powders are another example of a haemostatic product that is widely used. Examples of commercially available haemostatic powers, also known as styptic powders, include an adsorbable haemostatic gelatin powder (Spongostan® powder) and a calcium-loaded form of zeolite also known as QuikClot®. These haemostatic powders can be used to stop severe bleeding.
U.S. Pat. No. 5,614,587 describes collagen-based compositions useful in the attachment of tissues, or the attachment of tissues to synthetic implant materials. The compositions comprise fibrillar collagen, a fiber disassembly agent, and a multifunctionally activated synthetic hydrophilic polymer such as polyethylene glycol, wherein the collagen and synthetic polymer covalently bind to form a collagen-synthetic polymer conjugate.
WO 2004/028404 describes a tissue sealant composed of a synthetic collagen or synthetic gelatin and a electrophilic cross-linking agent which are provided in a dry state. In this international publication the crosslinker comprises an electrophilically activated (EA) poly (ethylene glycol) (PEG) or an EA PEG derivative such as PEG-succinimidyl ester, in particular PEG-succinimidyl propionate, PEG-succinimidyl butanoate, or PEG-succinimidyl glutarate. Upon wetting of this composition at an appropriate pH a reaction between the 2 components takes place and a gel with sealing properties is formed.
US 2011/0251574 describes a haemostatic porous composite sponge comprising a matrix of a biomaterial and a hydrophilic polymeric component comprising reactive groups wherein said polymeric component is coated onto a surface of said matrix of a biomaterial, or said matrix is impregnated with said polymeric material, or both. In a preferred embodiment the polymer is a polyalkylene oxide polymer, more particularly a multi-electrophilic polyethylene glycol (PEG). The matrix material can be selected from collagen, gelatin, fibrin, a polysaccharide (such as chitosan), a synthetic biodegradable biomaterial (such as polylactic acid or polyglycolic acid), and derivatives thereof.
US 2010/069579 a terminally activated polyoxazoline (POZ) compound, said POZ compound comprising a POZ polymer having a single active functional group on a terminal end thereof, said functional group capable of reacting with a group on a target molecule to create a target molecule-POZ conjugate wherein all the linkages between the target molecule and the POZ compound are hydrolytically stable linkages.
WO 2012/057628 describes crosslinked polyoxazoline polymers having tissue-adhesive properties due to the presence of electrophilic groups that are capable of reacting with nucleophile-containing chemical entities present in natural tissue.
It is an object of the present invention to provide a tissue-adhesive haemostatic product with improved properties.